BIOL111 invertebrates + vertebrates

metazoa 

multicellular organisms → animals 

animal proportion

89% of eukaryotic species

biomass percentage

• plants= 82%

• animals only 1%

• all other life = 17%

difference of biomass in plant vs animal 

• animals get around 

• not as tall as trees 

• no need for supporting structures 

animal sister group

choanoflagellate - from molecular phylogenetics

what is an animal?

• member of sister group of choanoflagellates 

• eukaryotic

• heterotrophic 

• multicellular

• mobile at some stage of life 

• diplontic life cycle 

• no cell walls

• diploid somatic cells

heterotrophic

use-preformed organic materials as energy and carbon source

modes of feeding

• predators

• detritivores

• omnivores

• filter feeders 

• herbivores

• parasites

other heterotrophic groups

• prokaryotes

• protists 

• plants

• fungi 

tissues

groups of similar cells organized into a single units

• can function together as organs to complete complex tasks 

protozoa

• used to be called unicellular animal 

• not a monophyletic group 

• have no close phylogenetic relationship with animals 

metazoa

animal taxa

protozoa examples

• ciliates 

• chaos/amoeba 

• plasmodium, causes malaria 

type of structural support 

• hydrostatic skeleton 

• exoskeleton 

• endoskelleton 

hydrostatic skeleton

• organism perform simple but efficient movement

• limited possibility for the attachment of limb 

• dependence of a humid environment

exoskeleton 

• firm, rigid structure 

• non living covering 

• in arthropods, doesn’t grow with animal 

• motling 

• ecdysozoans 

endoskeleton

• rigid structure inside the body

• vertebrates = living tissue 

• some invertebrate= non living

movement

reduces competition, enhances genetic diversity, expands distribution range

exceptions of diploid somatic cells

male honeybee

rotifers → female dominant

characters unique to animals

• neurons & nervous system 

• muscle cells 

• germ layers - blastula& gastrula stage 

evoluted early in the animal phylogenetic tree but not at its very root

prorifera

clade name of sponges

• earliest animals to appear in the fossil record

• 9000 species mostly marine

• sessile as adults, motile as larvae

• primitive features - specialized cells but no tissues or organs

• endoskeleton

clade

a monophyletic group or taxon

• includes the most recent common ancestor of a group of organisms and all its descendents 

are barnacle animals?

• semi parasitic

• crustaceans 

• exoskeleton 

nauplius larva

• barnacle larvae 

• allows them to spread → motile 

• common stage of many crustaceans 

diplontic

majority of life cycle spent on diploid stage

cleavage 

multiple rounds of rapid cell divisions - mitotic

→ formation of many cells from one cell (morula,blastula)

gastrulation

• in folding,invagination

• formation of embryonic tissue layers

• formation of head-tail axis 

morula

• hollow sphere- filled with fluid

• before gastrulation

• 32-64 cells 

endoderm

“inner skin”

→ digestive tract and repiratory 

ectoderm

• epidermis

• nervous system 

mesoderm 

• not in eveyr animal 

• mosrt internal organs 

• muscle cells 

• skeletal systems 

• gonads  

endoskeleton of sponges

spicules and a network of elastic fibers for support

sponge eating

• create strong water current for filter feeding 

• choanocytes = collar cells, choanoflagellate like cells 

• heterotrophic filter feeders 

spicules

• rigidity in extracellular matrix

• non organic matter 

• SiO2 

• CaCO3 

spongin

• proteins in extracellular matrix 

• flexible support 

sponge extracellular matrix

• non. cellular space 

• collagen and glycoproteins 

• some support provided 

bath sponge

high spongin content

glass sponges

high SiO2 content

sponge asexual reproduction

• fragmentation - not self induced , brought by a wave of predatord

• internal budding - clone of parent 

• nO MEIOSIS 

sexual reprodction of sponge 

• no gonads

• cells and eggs are produced in chanocytes or amoebocytes

• broadcast sperm

• sperm is trapped by choanocytes of a female sponge

• fertilized eggs develop in extracellular matrix

• motile larvae

cnidaria species

• jellyfish

• sea anemones 

• corals 

• hydrozoans 

cindaria

• 11 k species

• mostly marine

• microscopic to many meters long

• simple nervous system and muscular tissue

mesoglea

• act as hydroskeleton of cindarians

• provides structural support

• xtracellular matrix

• made of collagen and proteoglycans

cnidarian orientation

polyp - sessile

medusa - motile 

medusa

• motile 

• usually sexual stage 

• has mouth and tentacles 

polyp organization

• endoderm cells = taking up food

• external “ectoderm like layer”

• have sensory neurons - for light / temp 

• nematocytes → shootout poison 

radial symmetry of polyp

oral to aberal

cindarians nervous system

• simple nerve net - diffuse 

• no integration of signal 

• sensory information can come in from any direction 

how do cnidarians gain energy?

• carnivorous, inject prey with toxins and capture the prey 

• extracellular digestion in gastrovascular cavities 

• corals and anemones can obtain a large proportion of energy from symbiotic algae - dinoflagellates 

hydrozoa /hydra

• freshwater animal

• no medusa stage - polyp 

• moves by gliding, floating

• 2-5mm

portugese man of war

• tropical, subtropical oceans

• colonial polyps specialized for different function 

• gonozoiids , gastrozooids, dactylozooids 

• gaz filled float

• tentacles contain cnidoctes 

• up 50 m long tentacles 

pneumatophore

gas float at the top of portigese man of war

freshwater jellyfish

• hydrozoa 

• from asia 

• invading gatineau river 

scyphozoa 

• true jellyfish 

• large amount of mesoglea 

• some nematocyst strong enough to be felt by humans 

• prey on fish larvae and zooplankton 

• important for leatherback turtles 

cubozoa

• box jellyfish

• dangerous, lead to paralysis / death

anthozoa

• heterotrophic animals

• agregation of polyps 

sea anemones

• retract tentacles in defense

• tentacles have cnidocytes 

• predatory animal 

• mutualistic relationships with particular species of fish and shrimps 

corals

• form colonies of myriad of genetically identical polyps

• secrete calcium carbonate to form hard skeleton that becomes the framework of coral reefs 

• mutualistic relationship with dinoflagellates 

coral bleaching

• serious recent ecological problem

• zooxanthellae expelled → coral dies 

• brought by pollution, temp rising, bacteria causing disease 

ctenophores

• marine predators 

• “comb jellies”

shared characteristic of cnidaria and ctenophora 

• diploblastic 

• radial symetry 

• gelatinous body 

• tentacles 

• nerve and muscle cells 

unique features of ctenophora

• bioluminescence

• 8 rows of ctenes , comb-like ciliated plates for locomotion

• colloblasts- adhesive cells 

bilateria

all animalia excluding first two branches

platyhelminthes/flatworms

• 25k species

• aquatic/terrestrial 

• “free living” or parasites 

• 1mm/10m

cephalization

concentration of neurons and sensory structures at anterior end of animal

• sense organs probe environment 

• enables directed locomotion 

• cephalization is linked to directed movement 

flatworm sensory structures

• mechanoreceptors

• chemoreceptors

• photoreceptors

flatworm nervous system

• neurons at anterior end 

• primitive brain - two cerebral ganglia 

• longitudinal nerves 

turbellaria/ planarians

free living platyhelminths - the only one

• very few in freshwater/soil

• msot in sea water

parasitic platyhelminthes

• monogenea

• trematodoa 

• cestoda 

monogeneans

ectoparasites : mostly on frogs, reptiles, cepalotods

trematoda 

• flukes, endoparasites 

schistosomiasis

• caused by parasitic trematodes

• common in asia, africa and south america

• disease rarely causes death but damages organs and slows development

cestoda

• tapeworms, endoparasites

• host-specific

• no mouth , no digestive system

• protective cuticle forms around embryos and terminal proglottids break off, passed via feces

scolex 

suckers/hooks of tapeworms 

proglottids 

reproductive segments of tapeworms 

major evolutionary developments within bilateria

• mesoderms forms secondary body cavity

• fate of the blastopore 

• spiral vs radial cleavage 

the coelom fromation

• secondary body cavity

• blastocoel is primary body cavity 

• cells of mesoderm occupy primarily body cavity, then split in a way to themselves form a secondary body cavity.

annelida coelum

• secondary layer can be filled with liquid

• useful if you want to build external skeleton 

protostomia

blastopore develops into mouth, anus forms later

deuterostomia

blastopore develops into anus, mouth develops later

radial cleavage

new cells that are formed are smaller than old cells

• new cells lay exactly on top of old cells 

animals that do spiral cleavage

• mollusca 

• annelida 

• platyhelminths

trocophore larva

• a planktonic larval dispersal life stage common in both marine annelida and mollusca

annelida

• segmented worms or ringed worms

• body divided into metameres 

• 17 species 

• aquatic and terrestrial

• 0.5-3m

• coelom, used as a hydrostatic skeleton

metamerism of an annelid worm

linear repetition of similar body segments

→ observed externally and internally → nerves, blood vessels, excretory organs

regional differentiation

segments are similar but each can be modified

• brain, pharynx, specialization of gut organs 

advantages of metamerism

• multiple copies of organs 

• efficient nervous control - ganglion in each segment and faster control 

• increases body size by unit repition 

• regeneration

annelid NS

• anterior brain 

• ventral nerve cord 

• segmental ganglia 

polychaeta / bristle worms

• mainly marine

• detritivores, filter feeders 

• many have ees, palps, tentacles 

• parapodia- muscular flaps with setae , locomotion and respiration 

fan worms

• hydrothermal vents - symbiosis with chemosynthetic bacteria

oligochaeta

• terrestrial and few aquatic

• 10 k species 

• no parapodia, few setae 

• light sensitive cells 

• hermaphroditic

clitellium

organ from oligochaeta reproduction

• secretes a cocoon for embryo development - no specialized larvae stage 

hirudinea /leech

• mainly freshwater

• ectoparasitic and carnivorous 

• no setae 

• anterior and posterior sucker 

• hermaphroditic - no larval stage, clitellium 

mollusca 

• 85 k species 

• 2nd largest animal group after arthropods 

• both terrestrial and aquatic 

mollusca characteristics

• bilateral symmetry , triploblastic , protostomes with reduced coleom

• trochophore larvae

• major groups include polyplacophora, gastropoda, cephalopoda

unique molluscan traits

• mantle 

• radula 

• foot 

radula

rasping mouth organ for food uptake

mantle

• dorsal sheet of tissue 

• secretes shell or spicules 

• forms mantle cavity with gills - continuous with the sea for gas exchange 

foot of mollusca

ventral muscular organ for creeping movement